Attention recently has been directed to implementing a variety of communication services, including voice telephone service, over the worldwide packet switched data network now commonly known as the Internet. The Internet had its genesis in U.S. Government programs funded by the Advanced Research Projects Agency (ARPA). That research made possible national internetworked data communication systems. This work resulted in the development of network standards as well as a set of conventions, known as protocols, for interconnecting data networks and routing information across the networks. These protocols are commonly referred to as TCP/IP (transmission control protocol/internet protocol). The TCP/IP protocols were originally developed for use only through ARPANET but have subsequently become widely used in the industry. TCP/IP is flexible and robust. TCP takes care of the integrity, and IP moves the data.
The Internet provides two broad types of services: connectionless packet delivery service and reliable stream transport service. The Internet basically comprises several large computer networks joined together over high-speed data links ranging from ISDN to T1, T3, FDDI, SONET, SMDS, ATM, OT1, etc. The most prominent of these national nets are MILNET (Military Network), NSFNET (National Science Foundation NETwork), and CREN (Corporation for Research and Educational Networking). In 1995, the Government Accounting Office (GAO) reported that the Internet linked 59,000 networks, 2.2 million computers and 15 million users in 92 countries. However, since then it is estimated that the number of Internet users continues to double approximately annually.
In simplified fashion the Internet may be viewed as a series of packet data switches or `routers` connected together with computers connected to the routers. The information providers constitute the end systems which collect and market the information through their own servers. Access providers are companies such as UUNET, PSI, MCI and SPRINT which transport the information. Such companies market the usage of their networks to the actual end users.
FIG. 9 shows a simplified diagram of the Internet 349 and various types of systems typically connected thereto. Generally speaking the Internet consists of Autonomous Systems (AS) type packet data networks which may be owned and operated by Internet Service Providers (ISPs) such as PSI, UUNET, MCI, SPRINT, etc. Three such AS/ISP networks appear in FIG. 9 at 310, 312 and 314. The Autonomous Systems (ASs) are linked by high bandwidth Inter-AS Connections 311, 313 and 315. Information providers 316 and 318, such as America Online (AOL) and Compuserve, connect to the Internet via high speed lines 320 and 322, such as T1/T3 and the like. Information providers generally do not have their own Internet based Autonomous Systems but have or use Dial-Up Networks such as SprintNet (X.25), DATAPAC and TYMNET.
In some cases, the information provider 316 or 318 operates a host server or network of servers that their customers access by dial-up connection. If a customer wants information over and above that offered by the provider, the host server provides a tunnel connection through to the high speed link and the Internet 349. Other parties may connect into the network 349 at some other point and access information offered by provider 316 or 318 through the network 349.
By way of current illustration, MCI is both an ISP and an information provider, SPRINT is an ISP, and the MicroSoft Network is an information provider using UUNET as its ISP. Other information providers, such as universities, are indicated in exemplary fashion at 324 and are connected to the AS/ISPs via the same type connections here illustrated as T1 lines 326. Parties access information on servers of providers 324 via the Internet 349. Corporate Local Area Networks (LANs), such as those illustrated in 328 and 330, are connected through routers 332 and 334 and high speed data links such as T1 lines 336 and 338. Laptop computers 340 and 342 are representative of various personal computers and the like connected to the Internet via the public switched telephone network (PSTN) and are shown connected to the AS/ISPs via dial up links 344 and 346.
Recently, several companies have developed software for use on personal computers to permit two-way transfer of real-time voice information via an Internet data link between two personal computers, for example between PCs 340 and 342. In one of the directions, the sending computer converts voice signals from analog to digital format. The software facilitates data compression down to a rate compatible with modem communication via a POTS telephone line, in some cases as low as 2.4 kbits/s. The software also facilitates encapsulation of the digitized and compressed voice data into the TCP/IP protocol, with appropriate addressing to permit communication via the Internet 349. At the receiving end, the computer and software reverse the process to recover the analog voice information for presentation to the other party. These programs permit telephone-like communication between Internet users.
PCs having voice communication capabilities can conduct two-way, real-time audio communications with each other, in a manner directly analogous to a two-way telephone conversation. However, the actual signals exchanged between two such terminal devices go through the public packet data network. Typically, such communications at least bypass long distance interexchange carriers.
Internet based telephone programs have relied on servers (not separately shown) coupled to the Internet to establish voice communication links through the networks. Each person active on the network, who is willing to accept a voice call, must register with a server. A calling party can call only those persons registered on the voice communication server.
Subsequent new developments have provided systems which are capable of avoiding such registration problems. The common assignee's copending White and Farris application Ser. No. 08/670,908, attorney docket number 680-184, filed Jun. 26, 1996, entitled Internet Telephone service, describes such a system and is incorporated by reference herein in its entirety. In that system Public switched telephone networks utilizing program controlled switching systems are arranged in an architecture with the Internet to provide a methodology for facilitating telephone use of the Internet by individual customers on an impromptu basis. Provision is made to permit a caller to set-up and carry out a telephone call over the Internet from telephone station to telephone station without access to computer equipment, without the necessity of maintaining a subscription to any Internet service, and without the requiring Internet literacy or knowledge. Calls may be made on an inter or intra LATA, region or state, nationwide or worldwide basis. Billing may be implemented on a per call, timed, time and distance or other basis. Usage may be made of common channel interoffice signaling to set up the call and establish the necessary Internet connections and addressing. Calls may be made from telephone station to telephone station, from telephone station to computer or computer to telephone station.
The foregoing approach to Internet telephony is predominantly but not exclusively addressed to individual to individual communications. From a corporate or business standpoint the Internet is currently used principally for E-mail and data communication, the latter use providing a convenient mode of exchanging large data files. At the same time voice communication over corporate LANs and interconnection thereof by wide area networks (WANs) are known.
U.S. Pat. No. 4,866,704 to Larry A. Bergman, issued Sep. 12, 1989, entitled Fiber Optic Voice/Data Network, describes an asynchronous, high-speed, fiber optic local area network originally developed under a NASA contract for tactical environments. The network supports ordinary data packet traffic simultaneously with synchronous T1 voice traffic over a common token ring channel. A voice interface module parses, buffers, and re-synchronizes the voice data to the packet network employing elastic buffers on both the sending and receiving ends. Voice call setup and switching functions are performed external to the network with ordinary PABX equipment. Clock information is passed across network boundaries in a token passing ring by preceding the token with an idle period of non-transmission which allows the token to be used to re-establish a clock synchronized to the data. Provision is made to monitor and compensate the elastic receiving buffers so as to prevent them from overflowing or going empty.
U.S. Pat. No. 5,453,987 to Hai V. Tran, issued Sep. 26, 1995, entitled Random Access Protocol for Multi-media Networks, describes a method for randomly accessing a multi-media communications network defined by a common signal path and a plurality of voice and data terminals coupled to the common signal path for communication thereon. The method includes a first step of providing a plurality of sequential time slots for transmission of a plurality of information packets, each of the information packets having a length equal to a length of a representative one of the plurality of time slots. Next, each of the time slots is provided with an access field, an address control field and an information field. The access field of each of the plurality of time slots is next monitored for identifying a null time slot that is (1) in non-communication with any of the voice or data terminals, or (2) reserved for a voice terminal in a silence period. The next step of the method is to transmit a preamble to an access field of the identified null time slot. That transmission step is followed by the step of monitoring the transmission of the preamble for collisions between terminals competing for the identified null time slot. If no collision is detected, address data and information bits are transmitted in the respective fields of the identified null time slot and a respective time slot in subsequent data frames. If a collision is detected, then the method returns to the step of monitoring the access field of each of a plurality of time slots for identifying another null time slot, and then repeating the steps which are subsequent thereto.
U.S. Pat. No. 5,524,110 to Danneels, et al., issued Jun. 4, 1996, entitled Conferencing Over Multiple Transports, describes computer based audio/video conferencing in conjunction with data conferencing in a windowed environment The system provides real-time audio, video, and data conferencing between PC systems operating in non-real time windowed environments over two or more different transports.
The following listed patents also deal with varying aspects of the same technology: U.S. Pat. No. 4,663,758, issued May 5, 1987, U.S. Pat. No. 5,506,834, issued Apr. 9, 1996, U.S. Pat. No. 5,410,754, issued Apr. 25, 1995, U.S. Pat. No. 5,430,730, issued Jul. 4, 1995, and U.S. Pat. No. 5,375,068, issued Dec. 20, 1994.
There is a need for a system to provide to corporate and other large sized business organizations a convenient access to Internet telephony communication, while at the same time providing a reasonable degree of effective security along with convenience of access and administration.